1. Field of the Invention
The present invention relates to a method for adjusting the offset and scale of a galvano scanner system.
2. Description of the Related Art
A galvano scanner system is used for scanning a laser light in various laser machining devices in accordance with a fixed drive pattern. In the case that the system is used as a laser-marking device, for example, a galvano scanner system provided with an X-axis galvano scanner and a Y-axis galvano scanner is mounted in a laser machining device and laser light emitted from a laser light source is two-dimensionally scanned along a work surface by the scanners in accordance with a fixed drive pattern to provide predetermined markings on the work surface. A galvano scanner system is also used as a laser drawing device for projecting laser light onto a wall surface or the like.
In the final assembly step in a galvano scanner system, the scale (amount of movement of laser light on the workpiece surface in relation to an input command) and offset (distance by which the laser light spot formed on the workpiece surface deviates from the center position of scanning on the workpiece surface when the galvano scanner is positioned at the original position) of laser light irradiated onto the workpiece surface (scan surface) are adjusted. The adjustment work is generally carried out by irradiating visible laser light onto a workpiece surface and causing the light to conform to a scale on the workpiece surface while visually observing the laser spot on the workpiece surface. In the case of a galvano scanner system used in a laser drawing device that projects laser light onto a wall surface or the like, the scale is affected by the distance to the wall surface and the perpendicularity in relation to the wall surface. Therefore, the distance and the perpendicularity must also be adjusted.
Japanese Laid-open Patent Application 2003-220485 discloses a laser marking device provided with a function for using guiding laser light, which is visible laser light, to project, onto a workpiece via a galvano half mirror, a guide image that corresponds to a pattern to be printed. With the laser marking device, an irradiated point of guiding laser light is scanned onto a workpiece by rotating a galvano mirror on the basis of the same coordinate data in the same manner as during a print operation, and a guide image of the print pattern is projected onto the workpiece surface. The error between the projected position of the guide image and the desired position on the workpiece can be confirmed and the print position can be adjusted prior to the start of printing.
A method for adjusting the offset of a galvano scanner system and a method for adjusting the scale in a simple manner have not been proposed in the art. Also, a method has not been proposed in which the distance to the workpiece surface can be measured without affecting the scale adjustment and in which it can be determined if the light is sufficiently perpendicular in relation to the workpiece surface.
In view of the above, an object of the present invention is to provide a method for adjusting a galvano scanner system in which the offset can be adjusted in a simple manner.
Another object of the present invention is to provide a method for adjusting a galvano scanner system in which the scale can be adjusted with good accuracy in a simple manner on the basis of the measured distance to the workpiece surface and the determination of the perpendicularity in relation to the workpiece surface.